Esters of 16, 17-[3&#39;, 1&#39;-(3&#39;-carboxy-2&#39;-pyrazo-lino)] pregnen-20-ones and methods for their preparation



United States Patent Ofiice Patented Aug. 2, 1955 ESTERS OF 16,17-[3,1'-(3-CARBOXY-2-PYRAZO- LINO)]PREGNEN 20 ONES AND METHODS FOR THEIR PREPARATION George P. Mueller, Park Ridge, 111., assignor to G. D. Searle & Co., Chicago, Ill., a corporation of Illinois N Drawing. Application April 20, 1953, Serial No. 349,984

6 Claims. (Cl. 260-2395) The present invention relates to a new group of esters of pentacyclic pyrazolinecarboxylic acids and, more particularly, to esters of 16,17-[3,1-(3'-carboxy-2-pyrazolino)]pregnen-20-ones containing an oxygen atom attached to the carbon atom in position 3 of ring A.

The compounds which constitute this invention can be represented by the structural formula CH3 I/ wherein R is a member of the class consisting of lower alkyl and di-(lower)alkylamtino-(loweflalkyl radicals, =X is a member of the class consisting of and H (lower alkyl) radicals and wherein one unsaturated carbon to carbon linkage is attached to carbon-5 of the steroid nucleus. The location of the double bond in the pyrazoline nucleus is not established with certainty and, while the ultraviolet spectra favor the formula shown above, it is nevertheless possible that the formula should be drawn as CH3 N l C D CH In the foregoing structural formulas, R can represent a lower alkyl radical such as methyl, ethyl, straight and branched chain propyl, butyl and hexyl. R can also represent a di-(lower)alkylamino-(lower)alkyl radical of the type -Alk-N(lower alkyl)2 'wherein the lower alkyl groups are of the type mentioned above the Alk is a lower alkylene radical such as ethylene, propylene, butylene, trimethyene, tetramethylene, pentamethylene and hexarnethylene. The radical :X, at-

tached to carbon-three of the steroidal moiety, can be an oxo,

(lower alkyl) radical wherein the lower alkyl group is of the type mentioned above.

The compounds of my invention can be prepared by reaction of a 3-oxygenated 16-dehydropregnen-20-one of the type CHa with an excess of a diazoacetate.

This reaction provides valuable hormonal and cardiovascular agents with a normalizing effect on irregular heart action. The claimed esters can be hydrolized to the free 3-carboxylic acids. The latter serve as starting materials in the preparation of other esters and amides, and particularly of dialkylaminoalkylamides. Especially valuable hormonal and cardiovascular agents are obtained when the claimed esters are subjected to the pyrolytic reaction which yields the esters of the 3-oxygenated 16,17-carboxy- EXAMPLE 1 A mixture of '71 parts of 3-acetoxy-A -pregnadien- 20-one and 103 parts of ethyl diazoacetate is heated on an oil bath at 115-120 C. for minutes. There is an evolution of gas and the crystal cake melts slowly. On cooling a crystalline cake forms again. Successive recrystallizations from benzene and from methanol yield the ethyl ester of 3-acetoXy-16,17-[3'1-(3'-carboxy-2-pyrazolino)]-A -pregnen-20 one, melting at about 217-222 C. with decomposition. The compound has the structural formula (3H3 C=O NH CH3 1/ CHaCOO EXAMPLE 2 Ethyl ester of 3-aceloxy-16J7-carboxymethylene-A pregnen-ZO-one 40 parts of the ethyl ester of 3-acetoxy-l6,17-[3',1-(3- carboxy 2 pyrazolino)] A pregnen 20 one are mixed with boiling stones and heated under nitrogen for minutes at 230240 C. After cessation of the evolution of nitrogen, the product is cooled and taken up in 2800 parts of ether. The resulting solution is concentrated to one-half of its original volume and chilled to yield the ethyl ester of 3-acetoxy-16,17-carboxymethylene- A -pregnen--one in the form of long, fiat needles. Upon recrystallization from ether, needles are obtained melting at 225 .5226.5 C. This product presumably consists of the 16aB-isomer. A dioxane solution shows a specific rotation [u] ='-34.

The etheric mother liquors are concentrated and a benzene solution of the residue is applied to a silica gel chromatography column. Elution with a 5% solution of ethyl acetate in benzene yields first an additional quantity of material melting at about 2253-2265 C. and then a I CHsCOO EXAMPLE 3 A solution of parts of potassium hydroxide in 50 parts of water and parts of methanol is refluxed with a solution of 5 parts of the ethyl ester of 3-acetoxy-16,17- [3,1 (3' carboxy 2 pyrazolino)] A pregnen- 20-one in 800 parts of methanol for one hour under nitrogen. Then 400 parts of water are added and the mixture is chilled. A sufficient amount of dilute hydrochloricacid is added to the filtrate to lower the pH to about 4. The resulting solution is partially concentrated in vacuo. The precipitate is collected on a filter. The 16,17-[3,1-(3'- carboxy-2-pyrazolino) l-A -pregnen-3-ol-20-one melts at about 24l244 C.

EXAMPLE 4 A mixture of 3 1.4 parts of A -pregnadien-3-ol-20-one and 25 parts of ethyl diazoacetate is heated under reflux at 140 C. for one hour. Upon cooling a brown oil is obtained. The ethyl ester of 16,17-[3,1-(3'-carboxy- 2 pyrazolino)] A pregnen 3 o1 2O one shows ultraviolet absorption maxima at 290 and 317 millimicrons and infrared maxima at 2.92, 6.38 and 8.91 microns. It has the structural formula 16,1 7 -carb0xymethylene-M-pregnen-S -ol-20-0ne A solution of 4 parts of the 3-acetoxy-16,l7-carboxymethylene-A -pregnen-ZO-one in 360 parts of methanol is treated with a solution of 20 parts of potassium hydroxide in 50 parts of water and 40 parts of methanol. After standing for 12 hours the mixture is treated with 2000 parts of water and then with a sufiicient amount of dilute hydrochloric acid to lower the pH to 4. The reaction mixture is extracted with ether and the ether extract is dried over anhydrous sodium sulfate, filtered and evaporated to yield the 16,17-carboxymethylene-M-pregnen-3- ol-20-one, which is crystallized from methanol and then from ethyl acetate. The very fine needles melt at about 297302 C.

EXAMPLE 6 Methyl ester of 16,17- [3,1-(3'-carboxy2-pyrazolin0) A -pregnen-3-0l-20-0ne A mixture of 30 parts of A -pregnadien-3-ol-20-one and 21 parts of methyl diazoacetate is heated under reflux at 120-l40 C. for an hour. Upon cooling the methyl ester of 16,17-[3,1'-(3'-carboxy-2'-pyrazolino) J-A -pregnen-3-ol-20-one is obtained which has the structural formula CHa =0 NH CH3 0 CO 0 CH:

10 parts of this compound are mixed with boiling stones and heated for 15 minutes at about 225 C. under nitrogen. When the nitrogen development ceases, the product is cooled and dissolved in ether. The solution is washed with water, dried over sodium sulfate, filtered and .concentrated to yield the methyl ester of 16,17-carboxymethylene-A -pregnen-3-ol-20-one, which melts at about 235- 236 C.

The same ester is obtained by treatment of a solution of 3 parts of 16,17-carboxymethylene-A -pregnen-3-ol-20- one in 7000 parts of ether with an etheric solution of diazomethane prepared from 4 parts of nitrosomethylurea. Excess acetic acid is added and the ether solution "is washed with water, saturated sodium bicarbonate, water EXAMPLE 7 One part of 16, 17-[3',1-(3'-carboxy2-pyrazolino)]- A -pregnen-3-ol-20-one is treated With 20 parts of acetic anhydride and 20 parts of pyridine at room temperature for 20 hours and then poured on ice and water. The mixture is extracted withether and the ether. extract is Washed with dilute hydrochloric acid and water, dried over anhydrous sodium sulfate and evaporated. Crystallization from benzene and petroleum ether yields the 3-acetoxy- 16,17 [3,1 (3 car-boxy 2 pyrazolino)] A pregnen-ZO-one in crystals melting at 233.0233.6 C. The specific optical rotation of a dioxane solution is [u] =+209;5. The ultraviolet absorption spectrum shows a maximum at 272 millimicrons with a molecular extinction coeficient of 8408.

EXAMPLE 8 fl-Dimethylaminoethyl ester of 3 -acet xy-1 6,1 7 [3 ',1

(3 -carboxy-2 pyrazvlino) 1 -A -pregnen--one A solution of 5 parts of the ethyl ester of 3-acetoxy- 16,17 [3,1' (3 carboxy 2 pyrazolino)] A pregnen-ZO-one in parts of dimethylaminoethanol is brought to boiling and treated with a small amount of sodium. The slightly yellow solution is refluxed for 15 minutes and then cooled. The unreacted dimethylarninoethanolis removed by vacuum distillation and the residue is dissolved in parts of glacial acetic acid. This solution is poured into excess sodium bicarbonate solution. The latter is extracted with ether and the extract is washed with water and aqueous sodium chloride solution and dried over sodium sulfate; it is then filtered and evaporated. The residue is crystallized first from a mixture of acetone and petroleum ether and then from acetone with charcoal declorization. The p dimethylaminoethyl ester of 3 acetoxy 16,17 [3,1 (3-carboxy 2' pyrazolino)]A -pregnen-20-one melts at about 167.5-l C. The specific optical rotation of a dioxane solution is [u] =+175.9. The ultraviolet absorption spectrum shows maxirna at 290 and 317 millimicrons with molecular extinction coefficients of 8100 and 7300 respectively. The compound has the structural formula CHaCOO EXAMPLE 9 A mixture of 12 parts of 16,17-[3',l'-(3-carboxy-2- pyrazolino)]-A -pregnen-3-ol-20-one in 270 parts of isopropanol and 70 parts of ,B-chloroethyldiethylamine is refluxed for 4 hours, cooled and diluted with water. The solution is rendered alkaline by addition of dilute sodium bicarbonate solution and extracted with ether. This extract is dried over sodium sulfate, filtered and concentrated to yield the p-dietl'lylaminoethyl ester of 16,17-[3',l'-(3'- carboxy 2 pyrazolino)] A pregnen 3 ol 20 one in e in the form of needles which melt at about 9 3-9'5 C.

The compound has the structural formula 0:0 NH CH3 I/ EXAMPLE 10 fi-Diethylaminoezhyl ester of 16,17 carb0xymethylene-A pregnen-ZO-one A solution of 6 partsof 16,l7-carbolxymethylene-A pregnen'3-ol-20-one in 270 parts of isopropanol is refluxed for 4 hours with 2.7 parts of fi-chloroethyldiethylamine. The reaction mixture is then cooled, diluted with 3 volumes of water, made alkaline with aqueous sodium bicarbonate solution and extracted with ether. The extract is dried over calcium sulfate, filtered and concentrated to yield the p-diethylaminoethyl ester of 16,17-carboxymethylene-A -pregnen-20-one in heavy needles, which melt at about 151-153 C.

EXAMPLE 1 1 w C=O NH CH3 I/ o (I30 0 02115 EXAMPLE l2 Heating of 30 parts of 16-dehydroprogesterone and 21 parts of methyl diazoacetate yields the methyl ester of 1 6, 17- [3 ',1-(3 -carboxy-2'-pyrazolino)-] --A -pregnene- 3,17-dione which is isolated in the manner. described in the preceding example. This ester is heated under nitrogen for 15 minutes at 225 C. After cessation of the nitrogen development, the product is cooled and dissolved in ether. Concentration yields the methyl ester of 16,17-carboxymethylene-A -pregncue-3,17-dione. The same ester is obtained by the following procedure. In a nitrogen atmosphere a solution of 1.9 parts of the methyl ester of 16,17-carboxymethylene-A -pregnene-3- ol-20-one in parts of toluene is treated with 3 parts of aluminum isopropoxide in 15 parts of toluene and with 10 parts of cyclohexanone. After refluxing gently for an hour, the mixture is treated with 20 parts of a saturated aqueous Rochelle salt solution and then steam distilled for an hour. The residue is extracted with ether and the extract is washed with water, dried over sodium sulfate, filtered and evaporated to yield the methyl ester 7 8 of 16,l7-carboxymethylene-A -pregnene-3,l7-dione in 4. A compound of the structural formula crystals melting at 203-204 C.

I claim: CH3 1. A member of the class consisting of the compounds of the structural formulas CH i E on; i i & CH3 I I C 0 0(10wer alkyl) 0:0 NH

CH3 I I COOR 5. A compound of the structural formula CH: 0: (I311:

C=O NH and CH: l/

CH5 cy CH3 90 I 0 O OAlkN (lower alkyl) 1 0:0 NH CH5 I/ I 0: COOR V wherein Alk is a lower alkylene radical.

, 6. A compound of the structural formula XO- CH3 CH: wherein X is a member of the class consisting of hydrogen 0 H and (lower alkyl)-COradicals and R is a member CH3 1/ of the class consisting of lower alkyl radicals and radicals of the structural formula (lower alkyl)z-N-(1ower alkyl- 0/ CH6) (5O O-(lower alkyl) 2. A compound of the structural formula CH3 I (3H3 ontooo CH C=O NH C;N References Cited in the file of this patent I 0 1k UNITED STATES PATENTS war a y 2,161,928 Miescher June 13, 1939 2,664,423 Rorig Dec. 29, 1953 3. A compound of the structural formula I t O O 0Alk-N (lower alkyl) 2 wherein Alk is a lower alkylene radical. 

1. A MEMBER OF THE CLASS CONSISTING OF THE COMPOUNDS OF THE STRUCTURAL FORMULAS 